1. Field of the Invention
The present invention relates to a photoelectric conversion apparatus which is used in a scanner, a video camera, a digital camera, or the like.
2. Description of the Related Art
In recent years, there is such a tendency that a high speed is required in a photoelectric conversion apparatus. The method disclosed in the Official Gazette of Japanese Patent Application Laid-Open No. 2010-199710 (Patent Literature 1) is mentioned as one of units for realizing the high speed. According to Patent Literature 1, by using such a circuit construction that pixel signals of the same color are read out in parallel from a plurality of common output lines and color signals of a plurality of colors are read out from each common output line for one horizontal scanning period, a light weight of common output line capacitors is realized, thereby improving speed performance.
According to Patent Literature 1, a point that an amplifier unit is provided for each pixel column and a gain (amplification factor) of the amplifier unit can be switched in accordance with the color has been mentioned. If the gain differs in dependence on the color, noises due to a color selecting switch such as charge injection, clock feed through, or the like are generated, and a difference occurs between levels of the noise contained in the color signals. Thus, when a dark signal is read out, a step shaped signal level difference occurs between the color signals and appears as a stairway-shaped waveform when seen for the whole one horizontal scanning period. Such a distortion of the waveform becomes a factor which causes DSNU (Dark-Signal-Non-Uniformity) to deteriorate.
The invention is made in consideration of the foregoing problems and it is an aspect of the invention to provide a photoelectric conversion apparatus in which the DSNU is small.